In the surface finishing industry, machine tools are used to grind, cut, polish, lap, and finish the surfaces of plastic, metal, glass, and electronic components. An example would be grinding and polishing of plastic or glass optical lenses. These finishing processes utilize abrasives, polishing compounds, and coolants, all generally referred to as surface finishing compounds or slurries. The coolants generally are formulated with lubricants, rust inhibitors, and other surface active agents for cleanliness and low-foaming characteristics.
During the machine finishing processes, the surface finishing compounds become contaminated with impurities which may include plastic, glass, and ceramic particles, abrasive grains and binding agents, and other ferrous and nonferrous particles. The surface finishing compounds further are heated as a result of the friction generated during the machining processes.
It is economically desirable to recycle and reuse the surface finishing compounds which have been spent in the machine finishing process. This generally requires that the impurities be removed and the resulting surface finishing compounds be chilled to the desired cooling temperature. In certain unique circumstances, such as the use of rare earth oxide polishing compounds, it may be necessary to heat the finishing compounds to a desired temperature for best results.
The present filtering and cooling/heating systems for finishing compounds use a wide variety of options. Filtering is accomplished, among other methods, by: settling tanks; paper, fabric or cartridge media; hydrocyclones; or centrifuges. The finishing compounds and slurries generally are chilled or heated through a system of pumps and tanks or reservoirs. The surface finishing compound or slurry is stored temporarily in a storage tank or reservoir which has been fitted with refrigerant coils connected to a typical chiller. The chiller and coils chill the finishing compound to the desired temperature before it is reused in the process. When heating is desired, heater coils are used in lieu of refrigerant coils.
The problem, which is one of the bases for the invention, is that the present filtering and cooling/heating systems use a maze of filters, pumps and tanks to prepare the recycled surface finishing compounds. These systems are expensive to install, operate and maintain and take up extensive floor space at the site of the finishing processes.